Effect of Momordica charantia Fruit Juice on
Streptozotocin-induced Diabetes in Rats
Author: Eric H. Karunanayake, S. Jeevathayaparan, Kamani H. Tennekoon
Type of Publication: Pre-clinical
Date of Publication: 1990
Publication: Journal of Ethanopharmacology Vol. 30, pp. 199-204, 1990
Organization/s: University of Colombo
Abstract: The oral hypoglycaemic activity of Momordica charantia fruit juice was
investigated in rats with streptozotocin-induced diabetes. Oral administration of the
juice (10 ml/kg for 30 days) did not show a significant effect, either acute or
cumulative, on the ability to tolerate an external glucose load. The glycosylated
haemoglobin concentrations were significantly elevated in both juice-treated and
untreated diabetic rats and there was no significant difference between the two
groups. Viable bete-cells capable of secreting insulin upon stimulation appear to be
required for M. charantia to exert its oral hypoglycaemic activity.
The oral hypoglycaemic activity of Momordica charantia fruit juice was
investigated in rats with streptozotocin-induced diabetes. Oral administration of the
juice (10 ml/kg for 30 days) did not show a significant effect, either acute or
cumulative, on the ability to tolerate an external glucose load. The glycosylated
haemoglobin concentrations were significantly elevated in both juice-treated and
untreated diabetic rats and there was no significant difference between the two
groups. Viable bete-cells capable of secreting insulin upon stimulation appear to be
required for M. charantia to exert its oral hypoglycaemic activity.
Introduction
The oral hypoglycaemic activity of the fruit Juice of Momordica charantia L.
(family, Cucurbitaceae), a common vegetable in Sri Lanka and other Southeast Asian
countries, in non-insulin-dependent diabetics and in normal healthy laboratory
animals has been previously reported (Karunanayake et al., 1984; Welihinda et al.,
1986). Further, the fruit juice of M. charantia has been found to increase glucose
uptake by tissues in vitro and to increase the storage of glycogen by liver (Welihinda
and Karunanayake, 1986). The freeze-dried juice of M. charantia has been shown to
stimulate significantly insulin secretion by isolated beta-cells of the islets of
langerhans (Welihinda et al., 1982).
The present studies were undertaken to investigate further the possible
mechanism of oral hypoglycaemic activity of the fruit juice of M. charantia using
streptozotozin-diabetic rats as the animal model. Streptozotocin induces diabetes in
laboratory animals by a specific destruction of pancreatic bete-cells (Mansford and
Opie, 1968; Arison et al., 1967; Rerup, 1970; Hoftiezer and Carpenter, 1973).
Materials and Methods
Animal stock
In all experiments, male Sprague-Dawley rats weighing 195  21 g (mean 
S.D.) maintained on a standard laboratory diet (Moosaji’s Ltd, 34 W.A.D.
Ramanayake Mawatha, Colombo 2) were used. The animals were fasted overnight
(14-16 h) before the commencement of an oral glucose tolerance test.
Preparation of fuit juice of M. charantia
The frut juice of M. charantia was prepared in the manner of Karunanayake et
al., (1984). Fresh fruits (approximately 250 g in weight) were taken and seeds
removed. The fleshy parts were cut into small pieces and macerated using a mortar
and pestle. The producr was squeezed through a muslin cloth and the liquid
centrifuged at 5000 rev./min for 30 min under refrigeration. The supernatant
(approx. 100 ml) was used in the investigation. The fruit juice was administered at a
dosege of 10 ml/kg by oral intubation while the animal was under light ether
anaesthesia.
Induction of experimental diabetes
Streptozotocin (50 mg/ml) was dissolved in citrate buffer (0.01 M, pH 4.5)
immediately before administration. The drug was administered (50 mg/kg) via a
lateral tail while the animal was under light ether anaesthesia. The induction of
streptozotocin-diabetes was confirmed by the determination of fasting blood glucose
concentration on the third day post-administartion of streptozotocin.
Experimental with diabetic animals
Following the confirmation of streptozotocin-induced diabetes, the animals
were randomly divided into two groups. One group (N = 20) was treated with the
fruit juice of M. charantia (10 ml/kg) daily for 30 days and body weights recorded.
The control diabetic group (N = 18) received an equivalent amount of distilled water
under identical conditions.
Oral glucose tolerance test (OGTT)
At the end of the experimental period, OGTT was performed on two occasions
after an overnight fast in order to assess the acute and cumulative effects of M.
charantia on streptozotocin-induced diabetes. On the day of the OGTT, animals were
given an oral dose of glucose (10 ml/kg , 50% w/v) after collecting 50 l of blood for
fasting blood glucose estimation. Blood samples (50 l) were collected at 1-h
intervals for 3 h, with the first sampling commencing 1 h after the oral glucose load.
In investigating the acute effect, the glucose load was given 30 min after
administration of M. charantia to the treatment group and distilled water to the
control group. In investigating the cumulative effect, the oral glucose was given prior
administration of M. charantia or distilled water.
Determination of blood glucose
In all experiments, blood glucose concentration were assayed by the glucoseoxidase method (Hugget and Nixon, 1957).
Determination of glycosylated haemoglobin (HbA IC)
At the end of the experimental period,animals were killed and blood samples
(5 ml) were collected into heparinized tubes by cardiac puncture. Plasma was
separated and cells were washed twice (0.154 M saline) and stored at – 20 o C until
HbA IC concentration were determined by the method of Karunanayake and
Chandrasekharan (1986). The normal values for HbA IC in Sprague-Dawley rats of the
comparable age and weight were established by determining the HbA IC
concentration in 25 untreated Sprague-Dawley rats.
Results and Discussion
The result of oral glucose tolerance testing carried out on streptozotozindiabetic rats to evaluate the acute and cumulative effects of treatment with the fruit
juice of M. charantia are shown in Fig. 1 and 2 respectively. Although the percentage
increase in blood glucose concentration in Fig. 1 was consistently less in the juice
group than in the control group throughout the OGTT, these differences were not
statiscally significant. In the study of the cumulative effect (Fig. 2), the percentage
increase in blood glucose concentration were again consistently less in the juice
group than in the control group throughout the OGTT, but these differences were not
statiscally significant.
Glycosylated haemoglobin concentration in the treatment and control groups
as well as in a group of normal, apparently healthy rats of comparable age and body
weights are shown in Fig. 3. Glycosylated haemoglobin concentrations were
significantly higher (P < 0.001) in both the treatment and control diabetic groups
than in the normal group. However, there was no significant in the HbA IC
concentrations between the treatment and control diabetic groups.
Previous studies have shown that M. charantia juice stimulates insulin
secretions by isolated beta-cells (Welihinda et al., 1982) improves peripheral glucose
uptake (Welihinda and Karunanayake, 1986) and enhances the ability to tolerate an
external glucose load in non-insuln-dependent (maturity onset) diabetic patients
(Welihinda et al, 1986). These studies suggested a possible mechanism of action for
M. charantia juice by direct stimulation of the bete-cells to secrete insulin. The
diabetogenic action of streptozotocin has been shown to be due its highly specific
destruction of bete-cells (islets of Langerhans), thereby eliminating the source of
endogenous insulin (Rakienten et al., 1963; Rerup, 1970). The absence of any
significant acute or cumulative effect of M. charantia juice on the ability of rats to
tolerate an external load of glucose after streptozotocin treatment may, therefore,
provide further evidence to support the theory that the oral hypoglycaemic activity of
M. charantia juice is due to direct stimulation of insulin secretion.
The estimation of glycosylated haemoglobin as a parameter of metabolic
control in diabetes is now well established (Goldstein et al., 1982), particularly sine it
reflects the overall metabolic control present over the preceding 4 weeks. In the
present investigation, the treatment of streptozotocin-diabetic rats with M. charantia
juice commenced on the third day following induction of diabetes. The measurement
of glycosylated haemoglobin concentration at the end of the experimental period
showed significantly elevated HbA IC concentration in both the treated and control
diabetic groups when compared with the normal animals, but there was no
significant differences between the treatment and control groups. These data suggest
that M. charantia juice does not exert any apparent control on the homeostasis of
blood glucose.
In the light of the strong evidence that streptozotocin induces diabetes by
specific destruction of bete-cells, thereby eliminating the source of insulin, the
findings of the present study strongly suggest that viable beta-cells capable of
secreting insulin upon stimulation are essential for M. charantia juice to exert its oral
hypoglycaemic activity.
References
Arison, R. N., Ciaccio, E. I., Glitzer, M. S. and Pruss, M. P. (1967) Light and electron
microscopy of lesions in rats rendered diabetic with streptozotocin. Diabetes 16, 5156.
Goldstein, D. E., Parker, K. M. and England, j. D. (1982) Clinical applications of
glycosylated haemoglobin measurements. Diabetes 31 (Suppl. 3), 70-78.
Hoftiezer, V. and carpenter, A. M. (1973) Comparison of streptozotocin and alloxaninduced diabetes in the rat including volumetric quantitation of the pancreatic islets.
Diabetologia 9, 178-184.
Hugget, A. St. G. and Nixon, D. A. (1957) Use of glucose-oxidase, peroxidase and
dianisidine in the determination of blood and urinary glucose. Lancet 2, 368-370.
Karunanayake, E. H, Welihinda, J. , Sirimanna, S. R. and Sinnadorai, G. (1984) Oral
hypoglycaemic activity of some medicinal plants of Sri Lanka. Journal of
Ethnopharmacology 11, 223-231.
Karunanayake, E. H. and Chandrasekharan, N. V. (1985) An evaluation of a
colorimetric procedure for the estimation of glycosylated haemoglobin and
establishment of reference values for Sri Lanka. Journal of the National Science
Council of Sri Lanka 13, 235-258.
Mansford, K. R. L. and Opie, L. (1968) Comparison of metabolic abnormalities in
diabetes mellitus induced by streptozotocin or alloxan. Lancet 2, 670-671.
Rakienten, N., Rakienten, M. L. and Nadkarni, M. V. (1963) Studies on the
diabetogenic action of streptozotocin. Cancer Chemotheraphy Reports 29, 91-98.
Rerup, C. (1970) Drugs producing diabetes through damage of the insulin secreting
cells. Pharmacological Review 22, 485-518.
Welihinda, J., Arvidson, G., Gylfe, E., hellman, B. and Karlsson, E. (1982) The
insulin-releasing activity of the tropical plant Momordica charantia. Acta Biologica et
Medica Germanica 41, 1229-1240.
Welihinda, J. and Karunanayake, E. H. 91986) Extra-pancreatic effects of Momordica
charantia in rats . journal of Ethnopharmacology 17, 247-255.
Welihinda, J., Karunanayake, E. H, Sheriff, M. H. R. and Jayasinghe, K. S. a. (1986)
Effect of Momordica charantia on the glucose tolerance in maturity onset diabetes.
Journal of Ethnopharmacology 17, 277-282.